التفاصيل البيبلوغرافية
| العنوان: |
Near-field studies of anisotropic variations and temperature-induced structural changes in a supported single lipid bilayer |
| المؤلفون: |
Johnson, Merrell A., Decca, Ricardo S. |
| المساهمون: |
Physics, School of Science |
| المصدر: |
Publisher |
| بيانات النشر: |
American Physical Society |
| سنة النشر: |
2020 |
| المجموعة: |
Indiana University - Purdue University Indianapolis: IUPUI Scholar Works |
| مصطلحات موضوعية: |
lipid bilayer, anisotropic variations, temperature-induced structural changes |
| الوصف: |
Temperature-controlled polarization modulation near-field scanning optical microscopy measurements of a single supported Lβ′ 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) lipid bilayer are presented. The effective retardance (S=2π(ne−no)tλ, where t is the thickness of the bilayer and λ is the wavelength of light used) and the direction of the projection of the acyl chains (θ) were measured simultaneously. We demonstrate how one is able to align the system over the sample and measure a relative retardance ΔS, a crucial step in performing temperature-controlled experiments. Maps of ΔS and θ, with a lateral resolution on the order of ∼100 nm are presented, highlighting variations deriving from changes in the average molecular orientation across a lipid membrane at room temperature. A discussion of how this information can be used to map the average three-dimensional orientation of the molecules is presented. From ΔS and the known thickness of the membrane t the birefringence (ne−no) of the bilayer was determined. Temperature-controlled measurements yielded a change of ΔS∼(3.8±0.3) mrad at the main transition temperature (Tm∼41∘C) of a single planar bilayer of DPPC, where the membrane transitioned between the gel Lβ′ to liquid disorder Lα state. The result agrees well with previous values of (ne−no) in the Lβ′ phase and translates to an assumed average acyl chain orientation relative to the membrane normal (⟨ϕ⟩∼32∘) when T Tm. Evidence of super heating and cooling are presented. A discussion on how the observed behavior as Tm is approached, could relate to the existence of varying microconfigurations within the lipid bilyer are presented. This conversation includes ideas from a Landau-Ginzburg picture of first-order phase transitions in nematic-to-isotropic systems. |
| نوع الوثيقة: |
article in journal/newspaper |
| وصف الملف: |
application/pdf |
| اللغة: |
English |
| Relation: |
Physical Review E; Johnson, M. A., & Decca, R. S. (2020). Near-field studies of anisotropic variations and temperature-induced structural changes in a supported single lipid bilayer. Physical Review E, 101(3), 032416. https://doi.org/10.1103/PhysRevE.101.032416; https://hdl.handle.net/1805/27800 |
| الاتاحة: |
https://hdl.handle.net/1805/27800 |
| Rights: |
Publisher Policy |
| رقم الانضمام: |
edsbas.E3142C6B |
| قاعدة البيانات: |
BASE |